A unicyclist who took on the NYPD was victorious yesterday when a Manhattan judge tossed his ticket for riding a “bicycle” on the sidewalk.

“Unicycling is not a crime!” Isaih Rosemond, 18, crowed after Judge John Delury tossed the ticket the Brooklyn teen said he never should gotten in the first place, because it’s not against the law to ride one-wheelers on the sidewalk.

“The law doesn’t know the law,” he said.

Isaih was stopped on Rockaway Parkway in Canarsie on May 23 as he was riding his unicycle to Edward R. Murrow HS in Midwood.

He said a patrol car pulled up behind him and honked. He was surprised to see that the cop was cross.

“I just assumed they were going to ask me about my unicycle,” Isaih said.

But the female officer was in no mood for chitchat.

“Don’t you know it’s illegal to ride a bicycle on a sidewalk?” she snapped.

Isaih assured her unicycles aren’t banned from sidewalks and whipped out his iPhone to show her a government Web site that would prove it.

She didn’t want to see it and gave him a ticket that carried a possible maximum fine of $100.

Isaih was determined to challenge it.

His mom, Bernice Vertilus, said she was upset when he told her about it, but backed him “when he assured me he shouldn’t have gotten the ticket.”

She accompanied him to summons court yesterday, where his quest for justice got off to a rocky start.

In his first appearance before Delury, the judge offered him an adjournment in contemplation of dismissal, or ACD, meaning the ticket would be dismissed if he stayed out of trouble for six months.

Delury also warned him not to ride his bicycle on the sidewalk again “or I’ll put you in Rikers.”

Isaih explained it was a unicycle, but the judge didn’t budge.

After learning what an ACD was, Isaih didn’t want to take it — and asked to go back before the judge to ask for a trial.

Delury had read up on the law by Isaih’s second appearance and immediately declared the matter “dismissed.”

Isaih, who has been unicycling since February, was ecstatic.

“No more stress,” he said.

His mom was proud of her big wheel.

“I would have went for the ACD, but he has principles. He believes he’s correct, and he’s trying to fight for what he believes in,” Vertilus said.